EXECUTIVE SUMMARY. S.1 Introduction

Transcription

1 EXECUTIVE SUMMARY S.1 Introduction This Draft Environmental Impact Statement/Environmental Impact Report (EIS/R) was prepared by the United States Fish and Wildlife Service (USFWS) and the California State Coastal Conservancy, partnering with the California Department of Fish and Wildlife (CDFW; formerly the California Department of Fish and Game, CDFG), Santa Clara Valley Water District (SCVWD), the City of Mountain View, the City of Redwood City, and others to evaluate the potential environmental impacts of the proposed South ay Salt Pond (SSP) Restoration Project, Phase 2. S.1.1 SSP Restoration Phase 2 Project The SSP Restoration Project is a multi-agency effort to restore tidal marsh habitat, reconfigure managed pond habitat, maintain or improve flood protection, and provide recreation opportunities and public access in 15,100 acres of former salt-evaporation ponds purchased from and donated by Cargill, Inc. in Immediately after the March 2003 acquisition, the landowners, CDFW and USWFS, implemented the Initial Stewardship Plan (ISP) (USFWS and CDFG 2003) which was designed to maintain open and unvegetated pond habitats with enough water circulation to prevent salt production and provide some habitat values. The longer-term planning effort, a 50-year programmatic level plan for restoration, flood protection, and public access that included a first phase of projects, is described in the 2007 EIR/S, which addressed the SSP Restoration Project at both the program level and the Phase 1 level. This longer-term planning was facilitated by the California State Coastal Conservancy and completed in January of It was through this planning process that the SSP Restoration Project created the projects goals and objectives. These goals and objectives continue to guide the project to the present day. The SSP Restoration Project s planning phase was completed in January 2009 with the publication of the Final 2007 Programmatic EIS/R. Phase 1 implementation began immediately and was completed in It included the construction of 3,040 acres of tidal or muted tidal wetlands, 710 acres of enhanced managed pond, construction of habitat islands and improved levees, 7 miles of new public access and recreation trails, and other public access features. The selection and planning for Phase 2 projects started in 2010 and continues with this SSP Restoration Project Objectives 1. Create, restore, or enhance habitats of sufficient size, function, and appropriate structure to: Promote restoration of native special-status plants and animals that depend on South San Francisco ay habitat for all or part of their life cycles. Maintain current migratory bird species that utilize existing salt ponds and associated structures such as levees. Support increased abundance and diversity of native species in various South San Francisco ay aquatic and terrestrial ecosystem components, including plants, invertebrates, fish, mammals, birds, reptiles and amphibians. 2. Maintain or improve existing levels of flood protection in the South ay Area. 3. Provide public access and recreational opportunities compatible with wildlife and habitat goals. 4. Protect or improve existing levels of water and sediment quality in the South ay, and take into account ecological risks caused by restoration. 5. Implement design and management measures to maintain or improve current levels of vector management, control predation on special status species, and manage the spread of nonnative invasive species. 6. Protect the services provided by existing infrastructure (e.g., power lines, railroads). South ay Salt Pond Restoration Project Phase 2 July 2015 ES-1

2 Draft EIS/R. The ponds that were not part of Phase 1, nor planned to be part of Phase 2, will continue to be actively managed according to the goals set forth in the ISP, an Adaptive Management Plan (AMP), and the 2007 EIS/R until further implementation planning and the appropriate adaptive management studies are completed. The SSP Restoration Project is intended to tier from the analysis conducted for the 2007 EIS/R by advancing additional restoration activities within the SSP project area. The 2007 EIS/R assessed the environmental consequences associated with two long-term restoration alternatives. In consideration of the environmental consequences discussed in the 2007 EIS/R, the USFWS Record of Decision (ROD) and the CDFW Notice of Determination (NOD) state that the USFWS and CDFW will implement Programmatic Alternative C, which would eventually convert 90 percent of the former salt ponds to tidal marsh, while 10 percent would remain as enhanced managed ponds. Phase 2, as the second project component of this long term restoration project, would incrementally advance the project toward this end goal. Each of the Phase 2 Alternatives considered in this Draft EIS/R consist of various components that, if instituted, further advance the project toward achieving the 90/10 goal. Construction, operations, and maintenance of Phase 2 activities at one pond cluster would be independent from any activities at other Phase 2 pond. When considering and developing project alternatives for Phase 2, each pond cluster has been independently considered in meeting the targeted habitat designated in Program Alternative C (the 90/10 alternative), and separate sets of action alternatives were developed for each pond cluster. The Phase 2 project would be implemented at the Alviso-Island Ponds, the Alviso-Mountain View Ponds, the Alviso-A8 Ponds, and the Ravenswood Ponds. These pond clusters are located at the Don Edwards National Wildlife Refuge in Alameda, Santa Clara, and San Mateo Counties, California (See Figure ES-1, SSP Phase 2 Regional Location, and Figure ES-2, SSP Phase 2 Project Sites). In addition, the Phase 2 projects under consideration include two areas that are not within the Refuge boundary: the City of Mountain View s Charleston Slough and a small portion of land in the City of Menlo Park s edwell ayfront Park. Alternatives are proposed for each pond cluster, including a No Action Alternative. This EIS/R evaluates the following alternatives for each of the pond clusters. Alviso-Island Pond Cluster The Alviso-Island Ponds cluster (also referred to as the Island Ponds) consists of Ponds A19, A20, and A21, the levees surrounding each pond, and some of the fringe marsh outside of these levees including the narrow marsh between Ponds A19 and A20. Ponds A19, A20, and A21 are located in the eastern portion of the Alviso pond complex. These ponds are oriented east to west between Mud Slough to the north and west and Coyote Creek to the south. Mud Slough and Coyote Creek converge at the western edge of this pond cluster. The community of Alviso and City of Milpitas are located to the south and to the north and east, respectively. The ponds are geographically isolated from any urbanized and built-out areas by other waterbodies, other salt ponds, and a landfill. The former community of Drawbridge is located on a strip of land between Pond A21 and Pond A20. That strip of land also holds an active Union Pacific Railroad (UPRR) track. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-2

3 Figure ES-1. Phase 2 Regional Location South ay Salt Pond Restoration Project Phase 2 July 2015 ES-3

4 Figure ES-2. Phase 2 Project Sites South ay Salt Pond Restoration Project Phase 2 July 2015 ES-4

5 Under the No Action Alternative for the Alviso-Island Ponds cluster (Alternative Island A), no new activities would occur in Phase 2. Alternative Island and Island C propose activities that increase habitat complexity and improve the distribution of sedimentation and vegetation establishment of these ponds as they transition to tidal marsh. To increase complexity and connectivity of the Island Ponds and the waterways surrounding them, the activities proposed under these alternatives include breaches of the existing levees at various locations, removal or lowering of levees, and modification of existing breaches. Details about each Phase 2 alternative for this pond cluster are described below. Due to their geographic isolation, the SSP Restoration Project does not include recreation or flood control goals for these ponds. Therefore, no flood management or flood control activities or recreation components are proposed at these ponds for Phase 2. Each Phase 2 alternative at the Island Ponds is described below and illustrated on Figures ES-3 through ES-5. The Phase 2 Action Alternatives for this pond cluster are summarized in Table ES-1. Alternative Island A (No Action) Under Alternative Island A (No Action Alternative) no new activities would occur under Phase 2. The pond cluster would continue to be monitored and managed through the activities described in the AMP and in accordance with current USFWS practices. The existing breached levees would continue to be scoured from hydraulic action and naturally degrade. Ongoing monitoring and studies to track the progress of these ponds toward restoration as tidal marsh would be the principal component of the continued implementation of the AMP at this pond cluster. Ponds A19, A20, and A21 were breached on their southern sides in March 2006 as part of the ISP actions. The intent of the 2006 levee breaches was to bring tidal flows to these ponds and allow sediment to accrete until marsh plain elevation was reached. The unmaintained breaches would continue to scour from hydraulic action until equilibrium with the tidal flux is reached, and most levees would be allowed to degrade naturally. The levee containing the active railroad track would be maintained by UPRR to allow the continued use of the tracks. Under this alternative, this transition to tidal marsh would be allowed to continue. Aside from the monitoring and management activities of the AMP and maintenance of the railroad track, no other operation and maintenance activities would occur. Table ES-1 Components of the Phase 2 Action Alternatives at the Island Ponds ALTERNATIVE ISLAND reach north side of Pond A19 in two places. Lower or remove much of Pond A19 s northern and southern levees. Remove Pond A19 s western levee and Pond A20 s eastern levee to connect these two ponds. ALTERNATIVE ISLAND C reach north side of Pond A19 in two places. Lower or remove much of Pond A19 s northern and southern levees. Remove Pond A19 s western levee and Pond A20 s eastern levee to connect these two ponds. reach the north sides of Ponds A20 and A21. Lower portions of Pond A20 s northern and southern levees. Widen existing breaches on Pond A19 s southern side. Excavate two pilot channels within Pond A19. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-5

6 Figure ES-3. Alternative Island A South ay Salt Pond Restoration Project Phase 2 July 2015 ES-6

7 Figure ES-4. Alternative Island South ay Salt Pond Restoration Project Phase 2 July 2015 ES-7

8 Figure ES-5. Alternative Island C South ay Salt Pond Restoration Project Phase 2 July 2015 ES-8

9 Alternative Island Alternative Island would remove or lower the levees between Ponds A19 and A20 and lower westerly portions of the north and south perimeter levees of Pond A19 to increase connectivity and improve the ecological function of both ponds by altering circulation and sedimentation patterns in the ponds and improve the distribution of sediment accretion in Pond A19 and, to a lesser extent, in Pond A20. Alternative Island also includes some improvements for habitat quality for juvenile salmonids and other fish. Any levee material moved would be used locally to fill borrow ditches (ditches that were created to construct the original levees) or raise the pond bottom elevation and further speed revegetation. Alternative Island C Alternative Island C would include all of the components of Island with the addition of four components: levee breaches on the north sides of Ponds A20 and A21, lowering of portions of levees around Pond A20, pilot channels in Pond A19, and widening the existing breaches on the southern levee of Pond A19. These additional components are intended to further increase the habitat complexity and connectedness as this pond cluster transitions to tidal marsh. Levee material from lowering would be sidecast into the borrow ditches or pond bottoms to speed the return to marsh plain elevation. These actions would alter circulation and sedimentation patterns in the ponds and improve the distribution of sediment accretion in Pond A19 and to a lesser extent in Ponds A20 and A21. Similar to Alternative, improvements would be made for habitat quality for juvenile salmonids and other fish. Under Alternative C, the projected increase in sediment accumulation would help ensure that the rate of sedimentation accretion and marsh development would keep pace with expected SLR. Any levee material moved would be used locally to fill borrow ditches and further speed revegetation. Operation and Maintenance Aside from the monitoring and management activities of the AMP and continued maintenance of the existing railroad track, no other operation and maintenance activities would occur at the Island Ponds. The breaches would scour from hydraulic action until equilibrium with the tidal flux is reached, and most levees would be allowed to degrade naturally. The levee containing the existing railroad track would be maintained to allow the continued use of the tracks. Ongoing monitoring and studies to track the progress of these ponds toward restoration as tidal marsh are a component of the continued implementation of the AMP. Alviso-Mountain View Pond Cluster The Alviso-Mountain View pond cluster (the Mountain View Ponds) consists of Pond A1, Pond A2W, the levees surrounding each pond, some of the fringe marsh outside of the pond and slough levees, Permanente Creek, and Mountain View Slough. Charleston Slough, which is owned by the City of Mountain View and is not part of the Refuge, is included as part of the Mountain View pond cluster, as are the levees surrounding it. The Mountain View Ponds are in the western portion of the Alviso pond complex, between the Palo Alto Flood asin to the west, Mountain View Shoreline Park and Stevens Creek Marsh to the south, Stevens Creek to the east, and open bay water to the north. The 115-acre Charleston Slough is located at the western end of the cluster. Permanente Creek, which flows into Mountain View Slough, is located South ay Salt Pond Restoration Project Phase 2 July 2015 ES-9

10 between Ponds A1 and A2W. The cities of Mountain View and Palo Alto are located immediately inland of the pond cluster to the south and west, respectively. Under the No Action Alternative for the Alviso-Mountain View Pond cluster (Mountain View A), no new activities would occur as part of Phase 2. The action alternatives (Mountain View and Mountain View C) propose activities transitioning the ponds to tidal marsh while maintaining or improving existing flood protection along the pond cluster borders with the cities of Mountain View and Palo Alto. Viewing platforms and trails would be established to improve recreation and public access to the pond cluster. The SSP Restoration Project goals for this pond cluster are a transition to tidal marsh, maintain or improve flood protection, and improve recreation and public access. Restoration activities include breaches of levees at various locations, creation of wildlife habitat features, and other levee alterations to improve the overall ecological conditions of Pond A1, Pond A2W, and Charleston Slough. Upland fill material may be used to create habitat transition zones (relatively gently sloping areas), between the ecosystems of the ponds and the uplands at the top of the pond levees. Depending on the volume of material available, the constructed slope could be steeper than the planned 30:1 horizontal:vertical ratio, which would reduce the footprint area of the TZH. Upland fill material would also be used to create habitat islands and improve levees Alternative Mountain View C includes the additional incorporation of Charleston Slough into the project, as well as several actions that are necessary to provide additional flood protection to portions of the City of Mountain View and City of Palo Alto and to help maintain the water supply to the sailing lake in Mountain View s Shoreline Park. Each Phase 2 alternative at the Mountain View Ponds is described below and illustrated on Figures ES-6 through ES-9. The Phase 2 Action Alternatives for this pond cluster are summarized in Table ES-2. Alternative Mountain View A (No Action) Under Alternative Mountain View A, the No Action Alternative, no new activities would be implemented as part of Phase 2. The USFWS would maintain the ponds as part of the Don Edwards San Francisco ay National Wildlife Refuge System, following the AMP and other management practices. The pond cluster would continue to be managed through the activities described in the AMP and in accordance with current USFWS practices. The levees around Ponds A1 and A2W are classified as high priority levees to be maintained for inland flood protection. These outboard levees would be maintained (or repaired upon failure). The ponds would not be actively managed except for the current water quality management in Pond A2W, which involves circulating water as needed to control dissolved oxygen per the existing AMP. Existing trails on the levees along the boundary of the pond cluster would continue to be maintained. The current use of water in Charleston Slough to supply the water system the Shoreline Park would continue. Alternative Mountain View A is shown in Figure ES-6. The PG&E towers and power lines that run through Pond A2W and outside of it and Pond A1 would continue to be maintained as they are now (see Appendix D to the main text). These maintenance and repair activities include aerial and ground patrol, inspections, equipment inspections, electrical outage repair, and insulator washing and replacement. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-10

11 Figure ES-6. Alternative Mountain View A South ay Salt Pond Restoration Project Phase 2 July 2015 ES-11

12 Figure ES-7. Alternative Mountain View South ay Salt Pond Restoration Project Phase 2 July 2015 ES-12

13 Figure ES-8. Alternative Mountain View C South ay Salt Pond Restoration Project Phase 2 July 2015 ES-13

14 Figure ES-9. Alternative Mountain View C - Detail South ay Salt Pond Restoration Project Phase 2 July 2015 ES-14

15 Alternative Mountain View Under Alternative Mountain View, the Pond A1 and A2W levees would be breached at several points to introduce tidal flow in the ponds. Habitat transition zones and islands would be constructed in the ponds to increase habitat complexity and quality for special-status species. A new trail and viewing platform would be installed to improve recreation and public access at these ponds. Onsite cut material from breached or lowered levees and imported upland fill material would be used to raise levees, construct islands, or build transition zones. Table ES-2 Components of the Phase 2 Action Alternatives at the Mountain View Ponds ALTERNATIVE MOUNTAIN VIEW ALTERNATIVE MOUNTAIN VIEW C Do not include Charleston Slough in tidal marsh Include Charleston Slough in tidal marsh restoration. restoration. Raise and improve western levee of Pond A1. Lower and breach western levee of Pond A1. reach the west side of Pond A1 at one location. reach Pond A1 at three locations. reach Charleston Slough and connect it to Pond A1: Open Charleston Slough to full tidal exchange, by breaching the northern levee or by removing the tide gate structure itself, to allow vegetation to colonize the mud flats surrounding the slough s main channel; Raise and improve the western levee 1 of Charleston Slough, which separates it from the Palo Alto Flood asin; Raise the Coast Casey Forebay levee1 along southern border of Charleston Slough and associated sailing lake water intake and pump station structures; Add a primary water intake 2 for the Mountain View Shoreline Park sailing lake at the breach in the levee between Charleston Slough and Pond A1; Lower western levee of Pond A1; Rebuild the existing viewing platform along the Coast Casey Forebay levee; rebuild the existing trail and replace benches and signage along the improved western levee of Charleston Slough; and Armor levee on landward side of breach between Pond A1 and Charleston Slough. Construct bird habitat islands in Ponds A1 and A2W. Add bird habitat islands in Ponds A1 and A2W. Construct habitat transition zones across entire southern extent of Ponds A1 and A2W. reach Pond A2W at four locations. Armor the two eastern breaches of Pond A2W and add railcar bridges over the two breaches for Pacific Gas and Electric Company (PG&E) access. Raise concrete footings of PG&E towers in Pond A2W; elevate existing PG&E access boardwalk in Pond A2W; construct new sections of boardwalk from Pond A2W to connect to existing boardwalk over ay outside of the Palo Alto Flood asin. Construct a habitat transition zone across entire southern extent of Pond A1 but only across a portion of A2W. reach Pond A2W at four locations. Armor the two eastern breaches of Pond A2W and add railcar bridges for PG&E access and recreational trail access. Raise concrete footings of PG&E towers in Pond A2W; elevate existing PG&E access boardwalk in Pond A2W; construct new sections of boardwalk from A2W to connect to existing boardwalk over ay outside of Palo Alto Flood asin. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-15

16 Table ES-2 Components of the Phase 2 Action Alternatives at the Mountain View Ponds ALTERNATIVE MOUNTAIN VIEW Add viewing platform in Shoreline Park south of Pond A1. Construct spur trail on improved western levee of Pond A1 to a viewing platform. ALTERNATIVE MOUNTAIN VIEW C Add viewing platform in Shoreline Park south of Pond A1. Construct spur trail on improved west levee of Pond A1 to a viewing platform at the armored breach. Add a spur trail from ay Trail spine along Charleston Slough s northern levee to a viewing platform at or near the breach location. Add recreational trail on eastern and northern sides of Pond A2W to a bay side viewing platform near PG&E turnaround point. 1 The proposed improvements to the Coast Casey Forebay levee and the western levee of Charleston Slough would be to an elevation beyond that required by SSP Restoration Project s requirements; it would be higher to meet City of Mountain View s expectations for sea-level rise. 2 The proposed water intake at the A1-Charleston Slough breach location requires the intake, pipes, and sump to be constructed under the existing levee out to the breach. Alternative Mountain View C Under Alternative Mountain View C, levees would be breached and lowered to increase tidal flows in Pond A1, Pond A2W, and Charleston Slough. The inclusion of Charleston Slough into the SSP Restoration Project is the primary distinguishing feature between Alternative Mountain View C and Alternative Mountain View. Other actions would include adding habitat transition zones and habitat islands, and allowing for possible future connectivity with two brackish marshes south (inland) of Pond A2W. Proposed activities under Alternative Mountain View C are intended to increase habitat complexity and quality for special-status species. Flood control would be maintained with improvements to the southern and western levees of Charleston Slough. Several new trails and viewing platforms would be installed or replaced to improve recreation and public access at the pond cluster. Upland fill material would be imported into the ponds to raise levees, construct islands, or build habitat transition zones. To continue providing water to the City of Mountain View s Shoreline Park sailing lake, a new water intake would be constructed at the proposed breach between Pond A1 and Charleston Slough. The current water intake would be retained as a secondary intake source for backup, maintenance, etc. Operation and Maintenance Operation and maintenance of this pond cluster would be similar under Alternative Mountain View and Mountain View C. However, some of those maintenance activities would occur in different places (e.g., on the west levee of Charleston Slough instead of on the west levee of Pond A1) or over a larger or smaller area (e.g., Alternative C has more trails to maintain and fewer square feet of habitat transition zones). Otherwise, the operation and maintenance activities described below apply to both action alternatives. Operation and maintenance activities would continue to follow and be dictated by the 1995 Corps Permit #19009S98, applicable County operations, the CCP, and the AMP. PG&E would continue to operate and maintain its infrastructure, which would occur in coordination with the Refuge managers to ensure consistency with the operation and maintenance of the pond cluster. The City of Mountain View would continue to operate and maintain its properties that are adjacent to the pond cluster, which would also occur in coordination with the Refuge managers. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-16

17 Periodic maintenance of the pond infrastructure would be required following construction. Maintenance activities would require a maintenance staff person to travel to the pond cluster one or two times a week to perform activities such as predator control, general vegetation control, and vandalism repairs. AMP monitoring activities would occur, which would require additional workers (e.g., staff, consultants) to access the pond clusters. The frequency of visits to the pond cluster to conduct AMP monitoring activities would depend on the actual activities and would vary by season (e.g., during the bird breeding season there would be more trips to the site than during the non-breeding season). In Alternative Mountain View, the west levee of Pond A1 would require ongoing levee maintenance since it would provide flood protection. In Alternative C, this maintenance would instead take place on the western and southern levees of Charleston Slough. These levee maintenance activities would include placement of additional earth on top of, or on the sides of, the levees as the levees subside, with the level of settlement dependent upon geotechnical considerations. In general, pond levees which are improved to provide flood protection would likely exhibit the greatest degree of settlement. Levees that require erosion control measures would also require routine inspections and maintenance. If the levees that provide flood protection are improved to provide FEMA 100-year flood protection, a detailed levee maintenance plan would be required for certification to comply with FEMA standards. The northern perimeter levee, eastern levee, and northern portion of the western perimeter levee at Pond A1, and the western levee of Pond A2W would not be maintained and would be allowed to degrade naturally. The eastern and northern levee of Pond A2W would be maintained for PG&E access. Improved levees would be inspected and maintained for slope stability, erosion control, seepage, slides and settlement on an annual basis. Maintenance is expected to occur every 5 years to add additional fill material in areas where settlement occurs. Most of the maintenance would be accomplished during low tides and from levee crest. Maintenance of the nesting islands may require weed/vegetation removal as often as quarterly and placing fill material (sand, gravel and/or oyster shells) before the onset of nesting period every year. Nesting islands would also be periodically examined for erosion. Maintenance of habitat transition zones would include inspections and maintenance for slope stability, erosion control, seepage, slides and settlement on an annual basis. As necessary, vegetation removal would occur to prevent colonization of invasive species. Fill material would be placed, when needed, to respond to areas where erosion is observed. Additional maintenance activities may also be a need to address an AMP-specified management trigger. Public access and recreation features would be maintained as needed to keep trail surfaces safe and accessible. There would be a need for trash removal along trails and more intensely at staging areas and trailheads. The viewing platforms would be designed to minimize maintenance by utilizing durable and sustainable materials as much as possible to prevent degradation and the need for repeated maintenance. These would need to be checked periodically for defacement of interpretive boards and other forms of vandalism. Railcar bridges placed in publicly accessible areas, such as city streets and highways must be visually inspected every two years and may be required to report on the conditions every 5 years. In Alternative Mountain View, the bridges would not be publicly accessible, so this would not be required. However, because Alternative C would include a public access trail along the east levee of Pond A2W, the railcar bridges over the breaches there would need visually inspected and reported on as described above. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-17

18 The proposed bridges and the concrete abutments with wing walls at both ends of the bridge would be basically maintenance free for the design life cycle of 50 to 75 years. The bridges superstructures include main span girders, lateral bracing system, deck slab systems and safety railing that would need basic erosion protection maintenance work every few years. These activities include sanding, cleaning, and repainting as needed, which are common activities for all steel structures permeate exposed to weather. The PG&E towers, boardwalks, and power lines would be maintained in accordance with PG&E s current practices which are described in Appendix D. The maintenance of Pond A2W s east and north levees and the construction of new and improved boardwalks for PG&E s use would continue to provide the necessary access at the current levels. Alviso-A8 Pond Cluster The Alviso-A8 pond cluster (A8 Ponds) consists of Ponds A8 and A8S and the levees surrounding each pond. This pond cluster is located in the south-central portion of the Alviso pond complex, between the Guadalupe Slough and Alviso Ponds A5 and A7 to the west, Sunnyvale aylands County Park, Guadalupe Slough and San Tomas Aquino Creek to the south, Alviso Slough to the east and northeast, and San Francisco ay to the north. The cities of Sunnyvale and Santa Clara are located inland of the pond cluster to the south; a capped landfill lies to the southeast. The SSP Restoration Project set the initial goals for this pond cluster to be reversibly tidal habitat to address mercury concerns and later to possibly become fully tidal habitat, maintain or improve flood protection, and improve recreation and public access. Ponds A8 and A8S were physically connected in the Phase 1 actions and were made reversibly muted tidal habitat by removing parts of the levees (and associated vehicle access) between them and between Pond A8 and the adjacent Ponds A5/A7 to the west. A reversible, armored notch (smaller than a full breach that can be closed seasonally) was made in the eastern levee of Pond A8 to allow some muted tidal exchange and to allow the USFWS to vary the size of the notched opening. Ponds A8 and A8S are configured and managed such that they can also be used as flood storage basins during high-rainfall events. Pond A8 contains an overflow weir. During flood events greater than a 10- year flood in the lower Guadalupe River and Alviso Slough, water can overflow into Pond A8 for initial flood storage. There are currently no recreation or public access features at these ponds. Under Alternative A8 A (No Action), no new activities would occur under Phase 2. The Action Alternative (Alternative A8 ) would involve the placement of upland fill material to form habitat transition zones in the southwestern and southeastern corners of Pond A8S. Each Phase 2 alternative at the A8 Ponds is described below and illustrated on Figures ES-10 and ES-11. Alternative A8 A (No Action) Under Alternative A8 A, the USFWS would continue to operate and maintain the ponds in accordance with the AMP and other ongoing management practices that have been in place since the implementation of Phase 1 actions. These management practices include the wet season management of tidal exchange between Pond A8 and Alviso Slough to avoid fish entrainment and maintain existing levels of flood protection; inspections of pond infrastructure to ensure the pond is operating as intended, tidal connectivity is achieved as intended, and water quality requirements are being met; and monitoring of restoration performance. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-18

19 Figure ES-10. Alternative A8 A South ay Salt Pond Restoration Project Phase 2 July 2015 ES-19

20 Figure ES-11. Alternative A8 South ay Salt Pond Restoration Project Phase 2 July 2015 ES-20

21 Alternative A8 Alternative A8 proposes the construction of habitat transition zones in Pond A8S s southwest corner, southeast corner, or both, depending on the amount of material available. This document assumes both are constructed and analyzes the impacts associated with that assumption. The habitat transition zones would perform several functions: adding some flood protection, adding transitional habitat for salt marsh harvest mouse and Ridgway s rail, and protecting the adjacent landfill. Up to 1,400 linear feet of habitat transition zone would be established along the southwest corner of perimeter levee of Pond A8S, and up to 1,500 linear feet of habitat transition zone would be established along the southeast corner of perimeter levee of Pond A8S. The habitat transition zone for Alternative A8 would extend into the center of the pond at a slope of 30:1(h:v) or steeper, and would start at elevation 7.0 feet NAVD88. Operation and Maintenance The USFWS would continue to operate and maintain the ponds in accordance with the AMP and other ongoing management practices that have been in place since the implementation of Phase 1 actions. These ongoing management practices would not change during or after the construction activities described above. Ravenswood Pond Cluster The Phase 2 Ravenswood pond cluster consists of Ponds R3, R4, R5, and S5; the levees surrounding each pond; some of the fringe marsh outside of these levees; and the All-American Canal (AAC). The pond cluster is bordered by Menlo Park s edwell ayfront Park to the west, State Route (SR) 84 and the city of Menlo Park to the south, Ravenswood Slough to the east, and Greco Island and open bay water to the north. A small triangular pond is to the immediate west of Pond S5. This pond is unnamed and is labeled or described in various documents in three different ways: part of Pond S5, a separate but unnamed pond, or as the forebay of Pond S5. This document treats it as part of Pond S5 and frequently refers to it as the forebay. Under Alternative Ravenswood A (No Action), no new activities would be implemented as part of Phase 2. Alternatives Ravenswood, Ravenswood C, and Ravenswood D propose activities that would initiate the transition of Pond R4 from a seasonal pond to tidal marsh while maintaining or improving the existing flood protection and the conversion of Ponds R5 and S5 from seasonal ponds to a variety of enhanced managed pond habitat types. Upland fill material would also be placed in ponds to construct habitat transition zones in these ponds and enhance levees around them. In Pond R3, the existing western snowy plover (Charadrius alexandrinus nivosus) habitat would be improved by adding a water control structure to improve water circulation within the pond. Up to several hundred thousand cubic yards of fill in the form of appropriate upland material would be imported and used in Ponds R4, R5, or S5 to enhance levees, fill borrow ditches, and build the habitat transition zone. The majority of any imported fill material would be used for habitat transition zone and levee improvements; therefore, the information needed to assess the impacts of accepting and placing fill material is included in those parts of this project description. Viewing platforms and trails would be established to improve recreation and public access to the pond cluster. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-21

22 Each Phase 2 alternative at the Ravenswood Ponds is described below and illustrated on Figures ES-12 through ES-16. The Phase 2 Action Alternatives for this pond cluster are summarized in Table ES-3. Alternative Ravenswood A (No Action) Under Alternative Ravenswood A, the No Action Alternative, no new activities would be implemented as part of Phase 2. The USFWS would maintain the ponds as part of the Don Edwards San Francisco ay National Wildlife Refuge system following the AMP and other management practices. The Ravenswood pond cluster would continue to be managed through the activities described in the AMP. Ponds R3, R4 and R5/S5 would function as seasonal ponds. The outboard levees along Ponds R3 and R4 provide inland flood protection and would continue to be maintained or repaired as a component of the 1995 USACE operations and maintenance (O&M) permit. Trails of the adjacent edwell ayfront Park, owned by the City of Menlo Park, would continue to be used and maintained separately. Table ES-3 Components of the Phase 2 Action Alternatives at the Ravenswood Ponds ALTERNATIVE RAVENSWOOD ALTERNATIVE RAVENSWOOD C ALTERNATIVE RAVENSWOOD D Improve All-American Canal levee Improve All-American Canal levee Improve All-American Canal levee All-American Canal habitat transition zone edwell ayfront Park habitat transition zone edwell ayfront Park habitat transition zone All-American Canal habitat transition zone Pond R4 Northwest habitat transition zone Remove parts of Ponds R5 and S5 internal levees Remove parts of Ponds R5 and S5 levees Remove all of Ponds R5 and S5 internal levees Grade and partially fill Ponds R5/S5 Ponds R4/R5 water control structure Ponds R4/R5 water control structure Ponds R4/R5 water control structure Ponds R3/S5 water control structure Ponds R3/S5 water control structure Pond R3/Ravenswood Slough water control structure Pond R3/Ravenswood Slough water control structure Pond R3/Ravenswood Slough water control structure Connect to ayfront Canal and Atherton Channel Project Pond S5/Flood Slough water control structure Pond S5/Flood Slough water control structure Pond S5/Flood Slough water control structure Pond R4 pilot channel Pond R4 pilot channel Pond R4 east breach Pond R4 east breach Pond R4 east breach Pond R4 northwest breach Lower Pond R4 northwest levee Lower Pond R4 northwest levee Ponds R5 and S5 bird habitat island Ponds R5 and S5 bird habitat island Viewing platform near Pond R5 Viewing platform near Pond R5 Viewing platform near Pond R5 Pond R4 boardwalk trail at northwest Pond R4 trail on northwest levee corner Pond R4 viewing platform Pond R4 viewing platform Complete loop trail around Ponds R5 and S5 to connect to ay Trail Complete loop trail around Ponds R5 and S5 to connect to ay Trail South ay Salt Pond Restoration Project Phase 2 July 2015 ES-22

23 Figure ES-12. ayfront Canal and Atherton Channel Project South ay Salt Pond Restoration Project Phase 2 July 2015 ES-23

24 Figure ES-13. Alternative Ravenswood South ay Salt Pond Restoration Project Phase 2 July 2015 ES-24

25 Figure ES-14. Alternative Ravenswood C South ay Salt Pond Restoration Project Phase 2 July 2015 ES-25

26 Figure ES-15. Alternative Ravenswood D South ay Salt Pond Restoration Project Phase 2 July 2015 ES-26

27 Figure ES-16. ayfront Canal and Atherton Channel Project South ay Salt Pond Restoration Project Phase 2 July 2015 ES-27

28 Alternative Ravenswood Alternative Ravenswood would open Pond R4 to tidal flows, improve levees to provide additional flood protection, create habitat transition zone along the western edge of Pond R4, establish managed ponds to improve habitat for diving and dabbling birds, increase pond connectivity, and improve recreation and access. Surplus upland fill material (after completing the habitat transition zone and improving levees) would be used to fill borrow ditches and speed tidal marsh restoration. Alternative Ravenswood C Alternative Ravenswood C would be similar to Alternative Ravenswood with the following exceptions: Ponds R5 and S5 would be converted to a particular type of managed pond that is maintained at mud flat elevation for shore birds; water control structures would be installed on Pond R3 to allow for improvement to the habitat for western snowy plover; an additional habitat transition zone would be constructed; and additional recreational and public access components would be constructed. Alternative Ravenswood D Alternative Ravenswood D would open Pond R4 to tidal flows, improve levees to provide additional flood protection, create two habitat transition zones in Pond R4, establish enhanced managed ponds in Ponds R5 and S5, increase pond connectivity, enhance Pond R3 for western snowy plover habitat, remove the levees within and between Ponds R5 and S5, and improve recreation and public access. Alternative Ravenswood D would also allow stormwater outflow from Redwood City to Ponds R5 and S5 (via connections with the ayfront Canal and Atherton Channel), including open channel improvements, installation of a system of pipes or culverts, temporary removal of California Department of Transportation (Caltrans) stormwater pipes, and installation of a water control structure. This alternative would address a problem with residual salinity in Ponds S5 and R5 and would reduce flood risk in the neighborhood to the southwest. Operation and Maintenance All Action Alternatives Operation and maintenance activities for components of the pond cluster within the Refuge would continue to follow and be dictated by the 1995 Corps Permit #19009S98, applicable County operations, the CCP, and the AMP. The City of Menlo Park would continue to operate and maintain its properties that are adjacent to the pond cluster, in coordination with the Refuge managers. In Alternative Ravenswood D, the City of Redwood City would also coordinate its management and maintenance of the ayfront Canal and Atherton Channel water diversion system with other O&M activities, as described below. Periodic maintenance of the pond infrastructure would be required following construction. Maintenance would require a staff person to travel to the pond cluster one or two times a week to perform activities such as predator control, general vegetation control, and vandalism repairs. Operation of the water control structures would require additional staff visits. In addition, AMP monitoring activities would occur, which would require additional workers (e.g., staff, consultants) to access the pond clusters. The frequency of visits to the pond cluster to conduct AMP monitoring activities would depend on the actual activities and would vary by season (e.g., during the bird breeding season there would be more trips to the site than during the non-breeding season). South ay Salt Pond Restoration Project Phase 2 July 2015 ES-28

29 Ongoing levee maintenance would continue for existing levees that provide flood protection (as part of O&M activities described above and in consistency with the 1995 Corps Permit #19009S98 and the CCP). Levee maintenance activities would include the placement of additional earth on top of or on the pond side of the levees as the levees subside, with the level of settlement dependent upon geotechnical considerations. In general, pond levees that are improved to provide flood protection would likely exhibit the greatest degree of settlement. Levees that require erosion control measures would also require routine inspections and maintenance. The northern perimeter levee at Pond R4 would not be maintained and would be allowed to degrade naturally. Improved levees shall be inspected and maintained for slope stability, erosion control, seepage, slides and settlement on an annual basis. Maintenance is expected every 5 years to add additional fill material in areas where settlement occurs. Most of the maintenance work can be accomplished during low tides and from levee crest. If the levees that provide flood protection are improved to provide FEMA 100-year flood protection, a detailed levee maintenance plan would be required for certification to comply with FEMA standards. Water control structures would require inspection for structural integrity of gates, pipes, and approach way, obstruction to flow passage and preventative maintenance such as visual functionality of gates, seals, and removal of debris. In Alternative Ravenswood D only, these same activities would be required for the Redwood City stormwater connection. Inspection would be required every month until the first year and semi-annually thereafter. Maintenance would be required on an annual basis. O&M would be accomplished during low tides in Pond R4 and sloughs and by maintaining low storage conditions in the managed ponds. Maintenance of habitat transition zones would include inspections and maintenance for slope stability, erosion control, seepage, slides, and settlement on an annual basis. As necessary, vegetation removal would occur to prevent colonization of invasive species. Fill material would be placed, when needed, to respond to areas where erosion has been observed. Maintenance activities would also be dictated by the AMP if an AMP management trigger is reached, especially a trigger related to a biological resource (e.g., salt marsh harvest mouse) that would utilize habitat transition zone as habitat. Maintenance of public access and recreation features are similar but not identical across the Action Alternatives. The viewing platforms would be designed to minimize maintenance utilizing durable and sustainable materials as much as possible to prevent degradation and the need for repeated maintenance. All features would need to be checked periodically for defacement of interpretive boards and other forms of vandalism. Alternatives Ravenswood C and D would also include trail grooming to keep them safe and accessible. There would be a need for trash removal along trails and more intensely at staging areas and trailheads. Operations and maintenance of water levels in Ponds R3, R5, and S5 would differ across the three action alternatives, as described below. Alternative Ravenswood : The water levels in Ponds R5 and S5 would be actively managed year-round by opening and closing the water control structures as needed to maintain desired surface elevations, flows, and water quality. The salinity of these ponds would also be somewhat controlled through the use of the water control structures. USFWS Refuge staff would operate the water control structures and provide maintenance and cleaning as needed. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-29

30 The water levels of Pond R3 would be actively managed using one new water control structure to provide for the improvement of the existing western snowy plover habitat in Pond R3. USFWS Refuge staff would operate all of the water control structures and provide maintenance and cleaning as needed. Alternative Ravenswood C: The water levels in Ponds R5 and S5 would be actively managed year-round by opening and closing the water control structures as needed to maintain desired surface elevations, flows, and water quality. Water surface elevation in Ponds R5 and S5 would be managed to receive regular damped or muted tidal flows and maintain the pond bottoms at an intertidal elevation to form mudflats for shorebirds. The salinity of these ponds would also be somewhat controlled through the use of the water control structures. In addition, water would be controlled to flow into Pond R4 as needed for flood control as an overflow stormwater detention pond from Ponds R5 and S5 or other management purposes. The water levels of Pond R3 would be actively managed using two new water control structures to provide for the improvement of the existing western snowy plover habitat in Pond R3. USFWS Refuge staff would operate all of the water control structures and provide maintenance and cleaning as needed. Alternative Ravenswood D: The water levels in Ponds R5 and S5 would be actively managed year-round using the water control structures that would be installed as a part of meeting the habitat restoration goals of these ponds. Water surface elevation in Ponds R5 and S5 would be managed to create open water habitat for diving and dabbling ducks and other birds. Water levels would be maintained such that bottom depths are at subtidal elevations except during storm events. Prior to and during storm events when the tide in Flood Slough is high, the ponds would be drawn down to provide capacity for temporary detention of stormwater runoff from the City of Redwood City. Stormwater would enter into Pond S5 through new water control structures that would be installed to connect the Redwood City storm drain outflow to the forebay of Pond S5. This stormwater would then be discharged back into Flood Slough through a new water control structure between the pond and the slough when the tide is low and the slough can accept that volume of stormwater. The salinity of Ponds R5 and S5 would also be somewhat controlled through the use of the water control structures by receiving low salinity stormwater. Additionally, water would also be controlled to flow into Pond R4 as needed for flood control as an overflow stormwater detention pond from Ponds R5 and S5 or for salinity dilution or other management purposes. The water levels of Pond R3 would be actively managed using two new water control structures to provide for the improvement of the existing western snowy plover habitat in Pond R3. USFWS Refuge staff would operate the water control structures for habitat and water quality management purposes and provide maintenance and cleaning as needed.. S.2 Purpose of the EIS/R This EIS/R is intended to provide the public and responsible and trustee agencies with information about the potential environmental effects of the SSP Restoration Phase 2 Project. It will be used by the lead agencies when considering approval of the SSP Restoration Project. South ay Salt Pond Restoration Project Phase 2 July 2015 ES-30